The present invention relates to an improved safety-type gas washing sink for use in introducing gas through a metallurgical vessel into molten metal therein, the sink being of the type including a refractory wearable brick portion defining the first sink end to be exposed to the molten metal and that becomes worn during use, such wearable brick portion having therethrough gas flow paths for the passage therethrough of gas into the molten metal, and a refractory safety brick portion defining a second sink end to be directed away from the molten metal and through which the gas is delivered to the gas flow paths in the wearable sink portion.
This type of gas washing sink is intended to operate in a manner such that, upon the wearable brick portion becoming eroded or worn during use, the safety brick portion prevents a molten metal break through the sink by causing any such molten metal that reaches the safety brick portion to freeze or solidify. A gas washing sink of this type is disclosed in European EP No. 0 105 868. In such known arrangement the wearable brick portion is cemented or mortared into a recess in the safety brick portion, and a gas delivery pipe provided within the safety brick portion has a spiral shape. In the event of molten metal breaking through to the safety brick portion, the molten metal will enter such pipe and is intended to freeze therein. However, since the pipe is arranged within the safety brick portion, and such safety brick portion has a relatively low thermal conductivity, it is not entirely guaranteed that the molten metal will freeze within the pipe. As a result, prevention of molten metal breaking through the entire sink is not ensured by this known device.
A safety-type gas washing sink without a refractory safety brick portion is disclosed in European EP No. 0 181 853. The safety component of this known arrangement includes a metal core provided with a metal spiral member arranged in a gas delivery pipe beneath a wearable brick sink. In the event of molten metal breaking through the wearable brick sink, it is intended that such molten metal will freeze or solidify when contacting the metal core and metal spiral. However, in the event that the metal core and metal spiral themselves have reached a relatively high temperature, it cannot be guaranteed that the metal will freeze thereat. As a result, since the molten metal already will have penetrated into the gas delivery pipe in the event of a molten metal breakthrough, if the molten metal does not solidify at the metal core and metal spiral, then a complete breakthrough will occur. Furthermore, this known arrangement has the additional disadvantage that the metal core and metal spiral must be of substantial size and therefore occupy a substantial amount of space.